The present invention relates to the field of biotechnology, in particular to application of a GPR45 gene. The present invention discloses, for the first time, a correlation between GPR45 and obesity and also discloses that obesity may be caused if the GPR45 gene is knocked out or the expression of the GPR45 gene is reduced. Moreover, an obese mouse model is established by adopting a method of blocking the expression of the GPR45 gene for the first time, which is more similar to the mechanism underlying the obesity of human, is thus an ideal model for obesity basis and clinical application researches and can be well applied in screening of drugs for treating obesity.
