In the 1960s, the CPT grew in membership and support and by the early 1970s was the second largest communist movement in mainland Southeast Asia (after Vietnam).

[7] A CPT delegation attended the second national congress of the Communist Party of Vietnam (CPV) in Tuyen Quang in February 1951.

As of 1966, relations with the Communist Party of Vietnam began to deteriorate, as the CPT criticized the CPV for failing to take a clear pro-CCP stance.

[6] The Voice of the People of Thailand (VOPT), a CPT radio station, was established in Yunnan, southern China in March 1962.

The TPF was poised to fill the role of the united front in the triangular setting of the people's war strategy (party-army-front).

Concomitantly, the party began armed actions in the Na Kae District of Nakhon Phanom Province.

[11] As of 1968, the theory of neocolonialism was rejected by large sections of the party, who were inspired by Maoist positions arguing that Thailand was a semi-colonial country.

[13] In 1969, the Supreme Command of the People's Liberation Army of Thailand was formed, marking a new phase in the build-up of guerrilla forces.

[2] In the aftermath of the 6 October 1976 Massacre at Thammasat University and in the climate of increasing repression after the military take-over of the country, the CPT was able to expand its membership base.

A large section of the newly recruited members received political and military training in PLAT camps in Laos.

[6][15] In many cases, students accustomed to urban life had difficulties adapting to the harsh realities of guerrilla struggle, and thus the party decided to place many of them in villages rather deep in the jungle.

Following the expansion of its membership, the CPT began to stretch out a hand to wider sections of Thai society for forming a broad democratic front.

The nine-member coordination committee consisted of Aligned with the CPT at the time were also the Thai Moslem People's Liberation Armed Forces and the National Student Center of Thailand.

In late 1978, the Sino-Soviet split developed into armed hostilities in Southeast Asia as war broke out between Vietnam and Kampuchea, two countries that supported the CPT.

[2][16][17] Initially, the CPT adopted a neutral stance in the conflict between Vietnam and Kampuchea, causing relations to deteriorate with both the Chinese and the Vietnamese parties.

However, as Vietnam intervened militarily in Kampuchea, the CPT condemned the Vietnamese action in a statement issued on 7 June 1979.

The Chinese Communist Party began advising the CPT to tone down their revolutionary discourse against the Thai government in their radio broadcasts and to support Democratic Kampuchean forces against the Vietnamese.

[16] In 1982, the government, under Prime Minister General Prem Tinsulanonda, issued another executive order, 65/2525, offering amnesty to CPT-PLAT fighters.

The defectors generally rejected the Maoist ideological positions of the CPT, arguing that Thailand was emerging as an industrial nation and the peasant war strategy had to be abandoned.

[16] Damri Ruangsutham, an influential politburo member, and Surachai Sae Dan, a leading figure of the party in southern Thailand, were captured by state forces at that time.

According to a 1977 Kampuchean document, it was claimed that the General Secretary of the CPT was Khamtan (nom de guerre of Phayom Chulanont).