The purpose of this study is to discover whether the effect of learning objects force analysis by correct and incorrect combined worked-examples is better than by only correct combined worked-example. On this basis, the study further investigates whether the methods of error flag and correct and incorrect worked-examples paired combination can promote the effect of learning objects force analysis. This study designed three experiments to test the hypothesis. All experiments used objects force analysis diagram in first year high school physics textbook as the materials and middle school students of grade three participated in the study. A total of 160 subjects were selected through the pre-test. The experiments used single-factor design, independent variable level: correct and incorrect combined examples vs. correct examples; error flag vs. no error flag in correct and incorrect combined examples; correct and incorrect examples paired combination vs. correct examples. Experimental procedures included pre-test, grouping worked-example learning and post-test. The results of this study showed: (1) Learning effect of correct and incorrect combined examples group is significantly better than only correct combined examples group（F（1，59）=4.89，p< .05）; (2) Learning effect of correct and incorrect combined examples group with error flag is significantly better than correct and incorrect combined examples group without error flag（F（1，99）=7.23，p< .01）; (3) Learning effect of correct and incorrect examples paired combination with error flag is significantly better than only correct combined examples（F（1，59）=5.45，p< .05）. Conclusions of this study: (1)When middle school students use objects force analysis diagram to learn objects force analysis rules, the effect of correct and incorrect combined worked-examples is significantly better than only correct combined examples; (2)When middle school students use objects force analysis diagram to learn objects force analysis rules, the effect of correct and incorrect combined examples with error flag is significantly better than correct and incorrect combined examples without error flag. Error flag can significantly promote learning effect of objects force analysis rules; (3) Correct and incorrect examples paired combination with error flag can significantly promote learning effect of objects force analysis rules. In order to correct the error of objects force analysis in middle school, students can use correct and incorrect examples paired combination with error flag. This study further verifies the learning effect of correct and incorrect combined examples in objects force analysis. This study creates the error flag and correct and incorrect examples paired combination with error flag to promote learning effect of correct and incorrect combined worked-examples.