Objective The study aimed at establishing a formative assessment system for clinical practice of nursing undergraduates. Methods Literature review was used to develop a preliminary formative evaluation index system for clinical practice of nursing undergraduates. Two-round expert consultation was conducted among experts to construct the formative evaluation system for clinical practice of nursing undergraduates. Results The constructed formative evaluation index system for clinical practice of nursing undergraduates included two first-level indicators, eight second-level indicators, and 41 third-level indicators. The recovery rate of questionnaires of the two rounds were 100%(19/19) and 95%(18/19), respectively; the expert authority coefficient were 0.83 and 0.84, respectively；and the Kendall coordination coefficient were 0.123 and 0.209, respectively(P<0.05). The coefficients of variation for each level of indicators after the two rounds of expert consultation were 0, 0.05-0.16, and 0-0.16, respectively. Conclusion The expert consultation results in this study are highly credible, and the constructed formative evaluation index system for clinical practice of nursing undergraduates is scientific and reliable, which can provide reference for the formative evaluation of clinical practice of nursing undergraduates.