Abstract: To explore the effects of salt stress on the seed germination and seedling physiological characteristics of Lagerstroemia indica, seeds and seedlings of 12 cultivars were used as experimental materials. NaCl solutions were applied to simulate salt stress, with concentrations of 0, 50 and 100 mmol·L⁻¹ during the germination stage, and 0, 75 and 150 mmol·L⁻¹ during the seedling stage after preliminary screening. Relevant indicators of seed germination and seedling physiology were measured, and the membership function method and cluster analysis were employed to comprehensively evaluate salt tolerance at both stages. The results showed that the germination rate (GR), germination index (GI), vigor index (VI), and relative water content (RWC) of most cultivars generally decreased with the increasing NaCl concentration. Under high salt stress, ‘Huan Fen’ exhibited the highest GR and GI, ‘Honghuoqiu’ had the highest VI, and ‘Dahua Fenjing’ showed the highest RWC. Total chlorophyll (Chl) content and malondialdehyde (MDA) content generally increased, with the cell membrane permeability of ‘Dahua Fenjing’ being affected most by salt stress. The root-shoot ratio (R/Sr) and catalase (CAT) activity varied complexly under salt stress; the R/Sr of ‘Honghuoqiu’, ‘Baixue’, and ‘Jianming Hong’ increased, while CAT activity in ‘Huan Fen’, ‘Summer Dance’ and ‘PETIT PINK’ continued to rise. Through the membership function analysis of all indicators in the two periods, the salt tolerance of 12 cultivars from strongest to weakest was ranked, with the top three being ‘Honghuoqiu’, ‘Huan Fen’ and ‘Zishou’, and the last three being ‘PETIT PINK’, ‘PKES’ and ‘Dahua Fenjing’. Through the initial screening and identification of germplasm and seedling materials, the cultivars ‘Honghuoqiu’, ‘Huan Fen’ and ‘Zishou’ demonstrated better salt tolerance, providing a theoretical basis for the long-term observation of future planted cutting seedlings and the exploration of their salt tolerance ability at the genetic level.