Aim To explore the factors on behavior patterns of light/dark box(LDB)as an animal model of state anxiety in Kunming mice.Methods The behavior of adult,male,Kunming mice in LDB was recorded for five minutes,respectively.The following parameters were evaluated:percentage of time in the light area(Ltime%),percentage of squares crossing in the light area(Lcross%),percentage of rears in the light area(Lrear%),total number of squares crossing in the whole apparatus(Cross),total number of rears in the whole apparatus(Rear),total(Cross plus Rear),transitions between two areas(Transition),and number of fecal bolis in light box and dark box(Fbs).Subsequently,the factors,such as day-night rhythm,illumination area(L3/5 or L2/5 for ratio between Light box and Dark box:3:2 or 2:3,respectively),illumination color(in Dark box)and illumination intensity(in Light box),were investigated to screen the best experimental conditions.Results t-test showed that compared with night cycle,there was no significant difference in all LDB parameters during day cycle(P>0.05),while compared with 3/5 and 2/5,LDB parameters during day cycle such as Lcross%(t=5.363,P<0.01)in big area light box(L3/5),Lrear%(t=3.211,P<0.05)in small area light box(L2/5)increased statistically.The factorial design ANOVA showed that there was no significant difference in day-night rhythm on all LDB parameters(P>0.05),but a statistical influence of illumination area on Ltime%(F(1,20)=18.361,P<0.01),Lcross%(F(1,20)=49.148,P<0.01)and Lrear%(F(1,20)=8.424,P<0.01).The single factor ANOVA showed that there was significant influence of illumination color in dark box on Real(F(3,20)=3.746,P<0.05),Fbs(F(3,20)=3.585,P<0.05),and illumination intensity in light box on Cross(F(4,25)=2.569,P<0.05)and Total(F(4,25)=2.588,P<0.05).The Dunnett t test showed that compared with red color group,Rear(MD=-30.833,P<0.05)was significantly lower in yellow color group; while Cross(MD=-173.167,P<0.05)and Total(MD=-93.667,P<0.05)in 100 W group declined statistically compared with 15 W Group.Kruskal-Wallis test showed that there was no significant difference in illumination color and intensity on Fbs(P>0.05).Conclusions LDB as an animal model of state anxiety in Kunming mice can evaluate anxiety-,locomotion-exploration and emotionality- related behaviors,which cannot be affected by day-night rhythm,but illumination area(Ltime%,Lcross%,Lrear%),illumination color(Rear)and illumination intensity(Cross,Total).So it is recommended to adopt the uniform and fixed conditions,such as illumination area,color and intensity(less than 100 W).