This study was conducted for the purpose in detecting the effects of different plant densities on pho-tosynthetic-physiological characters and yield traits of the "compact-type" maize variety Chaoshi No. 1 grown in spring season on a super-high yielding paddy field. The results showed that in the range of plant densities from 67 500 - 97 500 plants/ha, with increasing of plant density, population leaf area index ( LAI) , leaf area duration (LAD) ,and capture efficiency of photo-synthetically active radiation ( PAR) of canopy increased correspondingly; the relative chlorophyll content ( SPAD ) and spicel leaf weight ( SLW ) decreased on the contrary; and the photochemical quenching( qP) and non-photo-chemical quenching( qN) of ear-nod leaf at grain filling stage increased, too. Under high plant density ( D3 ) condition, the effective quantum yield (EQY) of ear-nod leaf and the electron transport rate ( ETR ) showed low, indicating slow-down of the sunlight energy transformation efficiency; the speed of dry matter accumulation ( DMC) of a single plant decreased, but the population DMC and grain yield increased; the grain No. Per ear and 1000-grain weight decreased.%通过不同种植密度对“紧凑型”品种超试1号的群体光合生理性能及产量性状进行研究.结果表明,在6.75 ～ 9.75万株/hm2密度范围内,随着种植密度的增加,群体叶面积指数(LAI)显著增大,光合势(LAD)增加,冠层的光合有效辐射(PAR)的截获率增大,但叶片叶绿素相对含量(SPAD)降低和比叶重(SLW)下降；在灌浆期穗位叶PSⅡ反应中心光化学淬灭系数(qP)和非光化学淬灭系数(qN)随密度的增加而提高,但在高密度(D3)条件下PSⅡ光合量子产量(EQY)降低和电子传递速率(ETR)较低,表明其光能转化效率降低,而单株干物质积累速率随密度的增加则呈现降低趋势；但在群体干物质积累量(QDMC)表现为升高趋势,产量随密度的加大而提高,但同时导致每穗粒数和千粒重下降.
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