A molecular linkage map for the maize hybrid of cross between Ye478 and Dan340 was constructed by using 150 co-dominant SSR markers. The total map length was 1 478.7 cM with an average interval of 10.0 cM. Composite interval mapping was used to identify the plant height (PH) and ear position (EH) QTL at 5 environments based on the phenotypic data of 397 F2:3 families. Then 21 PH and 25 EH relevant QTL were identified. The mean contribution of 12.2% and 14.9% QTL for plant height was identified at the interval of umc2025 - umc1035 on chromosome 1 and umc1822 - bnlg1118 on chromosome 5, respectively. Meanwhile, the mean contribution of 10.2% and 22.8% to ear position were identified at the interval of phi029 - umc1102 on chromosome 3 and phi109188 - bnlg1118 on chromosome 5. The main QTL for PH and EH were both found at the regions of Bin5.05 - 5.07 on chromosome 5. The additive and partial dominant effects were the main genetic basis for plant height and ear position in maize. The effect of population size and environments on QTL mapping were analyzed.