This study was designed to investigate the response of plastic film mulch (MPF) and plant growth regulators (PGR) on maize yield and grain quality in spring and autumn seasons in the Hunan Province of southern China. The experimental design was randomized complete block design (RCBD) with four treatments and three replications. The treatments were: no mulch (CK), plastic film mulch (MPF), plant growth regulators (PGR) and MPF x PGR. In both the seasons, MPF x PGR treated plots gave highest maize yields (spring: 10.832 t/ha; autumn: 6.262 t/ha) followed by MPF (spring: 9.714 t/ha; autumn: 5.883 t/ha), and PGR (spring: 9.380 t/ha; autumn: 5.177 t/ha), while the control (spring: 8.592 t/ha; autumn: 5.085 t/ha) was the lowest. The mulch, PGR and MPF x PGR treatments had a negative significant (P< 0.05) effect on spring starch content. Crude fiber content was significantly different among treatment means in spring maize. The PGR treatment in spring had the highest crude fibre content (2.270%) followed by MPF x PGR (2.037%). There were negative significant differences among treatment means with respect to amino acid content in most cases except in glutamic acid, lysine, proline, alanine and leucine. The PGR x MPF treatment significantly gave the highest protein content (9.027%) followed by PGR (9.006%) and MPF (8.543%) in spring season. This is a significant achievement where a higher protein and lysine content has been achieved simultaneously.