Experiment on maize(Zea mays L.)hybrid Guiding 1 was done in Guangzhou in1988 and 1989.In different sowing date,spring crop had the longest growthperiod in comparison with summer crop,autumn and late-autumn crop,also had thelongest period from seeding emergence to panicle initiation and from panicleinitiation to heading or silking.There was a synchronous growth relations be-tween the stage of panicle initiation and unfolded leaves or leaf age index.