Background Chinese patients prefer physicians to initiate advance care planning (ACP) conversations, but there is no appropriate tool to evaluate physicians' ACP self-efficacy level in mainland China. This study aimed to translate the ACP self-efficacy scale into Chinese (ACP-SEc) and measure its psychometric properties among clinical physicians. Method The original scale was translated by literal translation, synthesis, and reverse translation, according to Brislin's translation model. Seven experts were invited to further revise the scale and evaluate the content validity. 348 physicians were conveniently sampled to evaluate the reliability and validity of the scale from May to June 2021 in 7 tertiary hospitals. Results The ACP-SEc contained 17 items, 1 dimension, with a total score of 17 to 85 points. In this study, the critical ratios of the items ranged from 12.533 to 23.306, the item-total correlation coefficients ranged from 0.619 to 0.839. The item-content validity index ranged from 0.86 to 1.00, and the average scale-level content validity index was 0.98. In total, 75.507% of the total variance was explained by 1 common factor. The results of confirmatory factor analysis showed that the fitting indices of the modified model were desirable. The ACP-SEc was moderately correlated with General Self-Efficacy Scale (r = 0.675, P < .001), and it differentiated between physician groups based on the knowledge level of ACP, palliative care or ACP-related training experience, attitude toward ACP, willingness to initiate ACP discussions with patients, and experience of discussing ACP with family and friends, willingness to initiate ACP discussions with family and friends (P <.05). The total Cronbach's & alpha; and test-retest reliability of the scale were .960 and .976, respectively. Conclusion The ACP-SEc shows good reliability and validity, and it can be used to assess the ACP self-efficacy level of physicians.