In order to evaluate the missing heritability of bipolar disorder, we queried the GWAS catalog of National Human Genome Research Institute, retrieve all the susceptible gene variation of bipolar disorder, and calculate the heritability explanation degree of each susceptibility variant using the multifactorial liability threshold model. The total heritability explanation degree of bipolar disorder was obtained through summing up the heritability explanation degree of each susceptibility variant. Then, we evaluated the missing heritability of bipolar disorder based on the total heritability explanation degree. The results showed that the total heritability explanation degree of bipolar disorder explained by known susceptible variants was 38.34%, and the other 61.66% of heritability can't be explained by known susceptibility variants, which belong to the missing heritability of bipolar disorder. The total heritability explanation degree of bipolar disorder in this study was significantly increased compared to earlier similar studies abroad. With constant discovery of new bipolar disorder susceptibility variants, the missing heritability of bipolar disorder has been greatly reduced, but the missing heritability of bipolar disorder still exists and occupies a large part of the bipolar disorder heritability, indicating that the molecular genetic mechanisms of bipolar disorder need to be further clarified.