Previous studies only focused on the individual social factors, without considering the overall social health patterns. The present study aimed to develop an integrated social health score (SHS) and investigate its associations with all-cause, cardiovascular disease (CVD), cancer mortality. A total of 330,716 participants (mean age 56.3 years; 52.4 % female) from UK Biobank was included between 2006 and 2010, and thereafter followed up to 2021. SHS was calculated by using information on social connections, social engagement and social support. Cox proportional hazards models was used to estimate the hazard ratios and 95 % confidence intervals (CIs) of the association between SHS and all-cause and cause-specific mortality and the 4-way decomposition was used to quantify the mediating effect of lifestyle factors. During a median follow-up period of 12.4 years, 37,897 death cases were recorded, including 4347 CVD and 10,380 cancer cases. The SHS was inversely associated with the risks of all-cause, CVD and cancer mortality in a dose-dependent manner (P for trend <0.001). The association between SHS with all-cause mortality was mediated by lifestyle factors including diet score, smoking status and alcohol consumption. Integrated SHS was inversely associated with risks of all-cause, CVD and cancer mortality, and the associations were partially mediated by lifestyle factors. Our study highlights the importance of maintaining high levels of social health by jointly enhancing social involvement, expanding social networks, and cultivating enduring intimate relationships across the life course. •The social health score was calculated based on information about social connections, engagement, and support, indicting better social health with higher scores.•Social health score was inversely associated with risks of all-cause, CVD and cancer mortality.•The association between social health score with all-cause mortality was mediated by lifestyle factors, including diet score, smoking status, and alcohol consumption.