Poor sexual and reproductive health status has been reported among rural-to-urban migrants in China. Therefore, some effective and feasible interventions are urgently needed. The authors developed a workplace-based intervention to compare 2 young labor migrant service packages (A and B) on the knowledge, attitude related to contraception, and contraceptive use among unmarried male migrants in Chengdu. Fourteen construction sites were randomly assigned to either of the 2 intervention packages. Interventions were completed in 3 months, and data were collected in 2 rounds independently (before and after interventions). After the intervention, the median scores for knowledge and attitude in migrants in package B were significantly higher than in migrants in package A. Although migrants in both packages increased use of condom, the increase was pronounced in migrants in package B, with odds ratio (OR) = 9.65 (95% confidence interval [CI] = 1.41-66.28). The rate of unwanted pregnancies was reduced more significantly in migrants in package B than in migrants in package A (OR = 0.16; 95%CI = 0.03-0.45). Unmarried male migrants who received the comprehensive intervention (package B) were more willing to use condoms and avoid unwanted pregnancies effectively.