：【Objective】This work tends to clarify the effect of MeJAspraying on floret opening time and plant type of japonica rice from diverse ecological areas and lay a scientific basis for utilizing MeJA to regulate the floret opening time of hybrid parents, increase seed production of intersubspecies hybrid rice【Method】Thirty fivejaponica rice cultivars from diverse ecological areas were used as test materials and subjected to different concentrations of MeJA treatment during heading date. Difference in response to MeJA exposure of the tested materials and its effect on plant type traits were analyzed.【Result】MeJA spraying had a significant promoting effect on the floret opening time of japonica rice from different ecological areas. Compared with the control, the floret opening time of japonica rice treated with different concentrations of MeJA was significantly advanced on the first day after treatment.With the rising MeJA concentration, the initial flowering time, full flowering time, and terminal flowering time of japonica rice were significantly advanced. The duration from initial flowering to full flowering, duration from initial flowering to terminal flowering were significantly shortened, duration from full flowering to terminal flowering was significantly extended. On the second and third days after treatment, MeJA spraying was out of function quickly. Flowering could be found under low concentration MeJA treatment and it was opposite under high- and medium-concentration MeJA treatment. Japonica rice cultivars from different ecological areas showed different sensitivity to MeJA regulation. The japonica rice cultivars from Liaoning rice growing region are the most sensitive in the floret opening time and those from the third accumulated temperature zone of Heilongjiang Province was the least sensitive. MeJA spraying exerted a significant effect on the plant type traits of japonica rice. Plant height and panicle curvature were significantly decreased with the increase of MeJA concentration as compared with the control. The length of the flag leaf and the second leaf from the top increased with the increasing MeJA concentration.【Conclusion】MeJA has significant promoting effect on the floret opening traits of japonica rice from different ecological areas. MeJA regulation has more obvious effect on early flowering with the rising concentration of MeJA. With the increase of MeJA concentration, the sensitivity of japonica rice to MeJAd differs. MeJA has a certain effect on plant type traits of japonica rice. Plant height, panicle curvaturesignificantly decrease with the increase of MeJA concentration. MeJA spraying exerts no significant effect on other plant type traits.