Objective To construct dopamine D2 receptor （D2R） gene low expression model in rat MMQ cells by RNA interference （RNAi） technique. Methods Three fragments of small interfering RNA （siRNA） were designed， which could induce decrease in D2R mRNA expression，then the plasmid was constructed to transfect the MMQ cells， and siRNA1， siRNA2， siRNA3， nontarget siRNA （siNT）， normal control （CTRL） groups were established. The expression of D2R protein was detected by Western blot. High interference expression cell line was chosen， and then adding bromocriptine （1 μmol/L）. Secretion of prolactin， relative expression of prolactin and prolactin mRNA level in MMQ cells after interference were observed by ELISA， Western blot， qRT-PCR. Results The relative expression levels of D2R protein was significantly different among the 5 groups （F=19.936，P＜ 0.001）. Among them， the relative expression levels of D2R protein in MMQ cells of siRNA1 and siRNA3 groups ［（0.23±0.12）， （0.57±0.24）］ were significantly different from those of siNT group （0.81±0.24） and CTRL group （0.94±0.21）（all P＜ 0.05）. siRNA1 and siRNA3 groups inhibited the repression of D2R protein in MMQ cells by 74% and 35%， respectively. After interference， there were statistically significant differences in secretion of prolactin， relative expression of prolactin and prolactin mRNA level of MMQ cells among the siRNA group， CTRL group and siNT group （F=10.898，7.485，7.898， all P＜ 0.05）. The secretion of prolactin of siRNA group was higher than that of siNT group and CTRL group ［（2.91±0.12） ng/ml vs （2.14±0.15） ng/ml， （2.09±0.44） ng/ml］. The relative expression of prolactin protein of siRNA group was higher than that of siNT group and CTRL group［（0.99±0.67）vs （0.85±0.13）， （0.82±0.12）］. The prolactin mRNA level of siRNA group was higher than that of siNT group and CTRL group ［（1.00±0.07） vs （0.69±0.09）， （0.73±0.14）］. All the differences were statistically significant （all P＜ 0.05）. Conclusions The constructed hyperprolact in MMQ cell model with low D2R expression by RNAi provides a reliable cell model for the target study of target drugs in the treatment of hyperprolactinemia