Two cold region japonica rice varieties Longjing 20 (more tillers and curved panicle type, MCP) and Longjing 21 (few tillers and halferect panicle type, FEP) were used as materials to study the effect of rowspacing on canopy structure, morphological traits and yield. The productive tiller percentage reduced first and then increased as rowspacing widened and followed a quadratic regression. Leaf area index (LAI) at later tillering stage and the highest stem number per unit area followed a quadratic regression, increasing first and then reducing. The effect of rowspacing on primary rachis branch was larger than on secondary rachis branch in Longjing 20 and the trend of Longjing 21 was reverse. The rowspacing showed a negative correlation with seed setting rates of secondary rachis branch and panicle. The correlation between rowspacing and yields of Longjing 20 and Longjing 21 was positive and significantly negative, respectively. The morphological traits of MCP were more easily affected by rowspacing and the rowspacing showed positive correlation with flag leaf length, flag leaf width, the 1st internode length from the top, the 2nd internode length from the top and panicle length. Otherwise，the morphological traits of FEP were not significantly affected by rowspacing. The wide rowspacing was propitious to accumulate dry matter of panicle, stem and leaf and to form yield in MCP (the best rowspacing of Longjing 20 was 30 cm), the narrow rowspacing was suit to Longjing 21 which has few tillers and half erect panicle (the best rowspacing of Longjing 21 was 21 cm). It was suggested that wide rowspacing was benefitial to improving population environment of MCP and narrow rowspacing was favorable to increase space utilization of FEP.
