Abstract: Objective To evaluate the relationship among social support, depression, loneliness and quality about the parents who lost their only child, and to provide reference for improving their mental health and quality of life from the perspective of social support. Methods From April 2018 to June 2018, 136 parents who lost their only child were included in the study. Scale of perceived social support (PSSS), Self-rating depression scale (SDS), California at Los Angels Loneliness Scale (PSSS), and Short-Form Health Survey Scale (SF-36) were assessed. The data were analyzed by SPSS 19.0. Results The PSSS score of the subjects was 45.75±11.62. The SDS scores of low PSSS group were higher than those of high PSSS group (t=2.658, P=0.009). The UCLA score of PSSS group was higher than that of middle PSSS group (t=2.062, P=0.042) and high PSSS group (t=2.907, P=0.005). The score of PSSS was negatively correlated with the scores of SDS and UCLA (r=-0.376, P=0.013, r=-0.412, P=0.011) respectively. The scores of MCS in low PSSS group were lower than those in middle PSSS group(t=-2.331, P=0.022) and high PSSS group (t=-2.478, P=0.015). The scores of PSSS were positively correlated with the scores of MCS (r=0.560, P=0.007). Conclusion Social support has a certain effect on depression and loneliness of the parents who lost their only child. Social support has no significant effect on the physical health of the parents who lost their only child, but has a significant impact on mental health, higher social support means higher mental health level.