Objective:To explore relationship amongpersonality,family interpersonal dynamics and college students'adaption.Methods:Adaption to college was assessed with the Symptom Checklist 90 (SCL-90)in internet when 1850 freshman selected conveniently from a university in Shanghai (Students with single factor score of SCL-90 equal or greater than 2.5 belonged to the positive group,while the other students with single factor score of SCL-90 all less than 2.5 belonged to the negative group).At the same time,they were evaluated with the Cattell's 16 Personality Factor(16PF)to evaluate their characteristics and Multi-Interpersonal Dynamics Questionnaire for Un-dergraduates (MIDQ-U)for undergraduate students to assess family interpersonal dynamics.Results:The scores of anxiety of 16PFwere higherin the positive groupwith 50 students than in the negative group[(7.2 ±1.4)vs.(4.6 ± 1.9),P <0.001 ],while the scores of extroversion,serenity and alertness of 16PF were lower in the positive groupthan inthe negativegroup.In the SCL-90 positive group,the MIDQ-Uscores of indifference and submissivenesswere higher[(17.3 ±6.0)vs.(14.9 ±4.2),(11.5 ±3.2)vs.(10.3 ±3.1);P <0.001]and the scores of indepen-dencewere lower than that in the positive group[(18.7 ±3.0)vs.(19.8 ±3.4),P =0.02].Path graphanalysiss-howed that anxiety and extroversionpartly predicted freshmen's adaption directly(β=0.57 --0.01 )and partly worked through indifference(β=0.031 --0.004),while decisivenesscompletely functioned through indifference with the coefficient of 0.008.Anxiety had part mediating effect between indifference and freshmen's adaption(β=0.008).In the other three factors,anxietyplayedcompletemediatingrole.Conclusion:Personalities and family inter-personal dynamics may affect each other,then mutually predictstudents'adaption to college.