Objective To explore the influence of the scores and weights of the regular grade on the evaluation of students' learning effect.Method To compare the impact of the regular grade before and after adjustment on the total mark,analyze the problems exposed during scoring and search for the solutions according to Medical Microbiology results of four grades including Grade 2010 to 2013.SPSS 13.0 software was used for statistical analysis and Pearson method was used for correlation analysis and theory achievement scores.Results The regular grade of four grades scored highly,with the average (95.00 ± 3.80),(96.00 ± 4.55),(95.00 ± 2.84) and (95.00 ±-2.82) respectively.What was more,it had randomness.The correlation coefficient between regular grade and total mark were 0.069,0.149,0.984 and 0.285 respectively.The regular grade of Grade 2010 was the same as Grade 2013 and the theoretical score of Grade 2013 was 4 points lower than Grade 2010(71 vs.75),however the total mark of Grade 2013 was 1 point higher than Grade 2010 (80 vs.79),which showed the more the regular grade weights,the greater it impacted on the total mark.Conclusion The appropriate score and weight of the regular grade is important to evaluate the students' learning effect objectively.