Objective To study the effect of interleukin-15 receptor α （IL-15Rα） gene knockout on the psychiatric disorders like behavior of mice. Methods 8-week old IL-15Rα knockout mice were divided into homozygous and heterozygous groups， and wild-type mice were used as controls. The genotypes of mice were identified by polymerase chain reaction （PCR）. The neuropsychological behaviors were analyzed by nest building test， social interaction test and sucrose preference test. Results The results of PCR showed that the bands of wild-type， homozygote and heterozygote were 171 bp， 280 bp and 171 bp and 280 bp respectively. In this study， 8 wild-type， 14 heterozygotes and 12 homozygotes were included for behavioral testing. （1） Nesting score： Compared with the wild-type， the homozygous knockout mice showed significant nest building dysfunction. The nesting score （1.58±0.79） of homozygous knockout mice was significantly lower than that of wild-type mice （2.71±0.95， P＜0.05）. At the same time， the nesting score of heterozygous mice （2.21±1.05） was between that of wild-type and homozygous group. Compared with the wild-type and homozygous group， there was no statistical significance （P＞ 0.05）. （2） Three-chamber social test： The data showed that there was no significant difference in the walking distance and walking time of the homozygous knockout mice in the strange mice chamber compared with the empty chamber ［Walking distance （22 395±8 664） mm vs （18 057±3 438） mm； Time （178.5±49.05） s vs （161.1±49.84） s； t=1.612， 0.865 respectively； P＞ 0.05］. The walking distance of the heterozygous group in the strange mice chamber was significantly longer than that in the empty chamber ［（25 454±12 106） mm vs （16 618±7 542） mm； t=2.295； P=0.030］. The walking distance and walking time of the wild-type mice in the strange mice chamber was significantly higher than those in the empty chamber ［（21 358±5 278） mm vs （14 800±4 726） mm， （190.4±70.36） s vs （102.0±32.64） s； t=2.267， 2.573 respectively； P ＜ 0.05］. （3） Sucrose preference test： IL-15Rα knockout mice showed no obvious anorexia. Compared with the sucrose preference ratio of wild-type mice， there was no statistical significance in that of homozygous （80.02±16.59） % and heterozygous （84.84±6.53） % mice （P ＞ 0.05）. Conclusions IL-15Rα knockout mice showed obvious psychiatric disorders like behaviors， including nesting and social dysfunction， but did not show depressiverelated pleasure loss behavior.