Objective To explore the characteristics of psychological stress of students from five-year program in clinical practice, so as to provide reference basis for promoting medical students' mental health and formulating scientific clinical practice plan. Methods Totally 318 students from five-year program of Sun Yat-sen University enrolled in 2016 and 2017 were selected as research objects,and the questionnaire for investigating general situation and the scale of psychological stress during clinical practice were used to carry out the survey. The difference between groups was analyzed by t-test, analysis of variance, snk-q test and χ² test. Results The score of psychological stress during clinical practice was (3.00±1.02). The scores of stress during clinical practice, stress on self-development and career choice, personal life and social activity were (2.68±0.74),(2.57±0.82),(2.52±0.79) and (2.11±0.74) respectively. The score difference among the dimensions was statistically significant (P<0.001). The students from rural area had higher scores of total stress (2.62+0.74) than those from urban areas (2.45+0.71). The total stress score of medical students with family economic stress (2.73±0.76) was higher than that of medical students with well-off(2.01±0.66). The total stress score of introverted medical students was higher than that of cheerful medical students with the scores as (2.80±0.84) and (2.34±0.71) respectively. The differences were statistically significant (all P<0.05). Conclusions Clinical undergraduates are faced with the pressure from clinical practice, social life, self-development and career selection during clinical practice, and influenced by family economics, registered residence and personality. Medical educators should pay attention to their psychological pressure and influencing factors, and to formulate scientific clinical practice to reduce their psychological pressure.