[en] The present research is an attempt to study the psychological effects of long-term exposure to low-level X-ray on man. The subjects included 50 exposed people and 50 control. The battery of psychological tests consists of 10 subtests mainly involving memory and coordination ability. The results indicate that there are no statistical differences in all subtests between exposure and control group, but exposure group appears to be a little lower on most subtests about memory. With age, decline of psychological function is observed in all subtests in both groups. The subjects are further divided into three subgroups according to the number of X-ray exposed years. No statistical differences are found in all subgroups between exposure and control. Factor analysis has been made and two factors are obtained. factor 1 is mainly about speed of coordination, factor 2 is mainly about memory and attention. No statistical differences in factor scores are observed in all subgroups between exposure and control. Yet decline is found in factor 1 and factor 2 in both exposure and control groups with age. The results show that there is no significant effect of current dose level of X-ray exposure on human psychological function