Abstract: A population including 427 germplasm resources, crossed by female parent Populus euramericana I108 and male parent Populus szechuanica var. tibetica were used to construct the genetic linkage map in seedling stage. The map contains 37 SSR makers and 6 linkage groups spanning 9691cM with an average of 2514cM between markers. Genemap software was used to draw the marker linkage map. The four phenotype indicators of height (hs), single leaf photosynthetic rate (Pn), intercellular CO2 concentration (Ci), transpiration rate (Tr) are in line with normal distribution. The interval mapping method of software package MAPMAKER were used to map andanalyze QTLs. 8 QTLs were detected for seedling growth and photosynthetic trait. 3 QTLs were detected for seedling height which explained 164%, 201% and 178% of the phenotypic variation. 2 QTLs were detected for photosynthetic rate which explained 102% and 137% of the phenotypic variation. 2 QTLs were detected for Intercellular CO2 concentration which explained 67% and 83% of the phenotypic variation. 1 QTL was detected for transpiration rate which explained 97% of the phenotypic variation.