The 1970–71 I liga was the 45th season of the Polish Football Championship and the 37th season of the I liga, the top Polish professional league for association football clubs, since its establishment in 1927.

The league was operated by the Polish Football Association (PZPN).

The champions were Górnik Zabrze, who won their 9th Polish title.

The season started on 8 August 1970 and concluded on 23 June 1971 (autumn-spring league).

A total of 14 teams participated, 12 of which competed in the league during the 1969–70 season, while the remaining two were promoted from the 1969–70 II liga.