Abstract: Objective To explore the influence of professional identity on positive academic emotions among medical students at public expense in Shandong Province,and to verify the mediating role of psychological capital and the moderating role of achievement motivation. Methods From February to March 2022,a convenient sampling method was used to select 285 medical students at public expense from a university in Shandong Province. A questionnaire survey was conducted using the rural order oriented medical students' occupational identity scale,achievement motivation scale,psychological capital scale,and positive academic emotion scale. Results The scores of professional identity,positive academic emotions,psychological capital and achievement motivation of medical students at public expense in a university in Shandong Province were （93.19±13.11）,（78.88±12.51）,（127.93±18.86）,（-2.01±9.20）points,respectively. There were significant positive correlations between the variables of professional identity,positive academic emotions,psychological capital and achievement motivation of medical students at public expense（r=0.203-0.651,all P<0.05）.Psychological capital partially mediated the relationship between professional identity and positive academic emotions（95%CI：0.070-0.263）,with an effect value of 0.16; achievement motivation moderated the first half of the mediation process between professional identity and positive academic emotions through psychological capital（β_high=0.294,β_Low=0.254,P<0.01）,the second half of the path（β_High=0.583,β_Low=0.482,P<0.01） and the direct path（β_High=0.531,β_Low=0.462,P<0.01）. Conclusion The professional identity of medical students at public expense not only directly affects positive academic emotions,but also indirectly affects positive academic emotions through the mediating effect of psychological capital,and achievement motivation plays a moderating role.

Key words: Medical students at public expense, Professional identity, Psychological capital, Achievement motivation, Positive academic emotions