Sodium-ion batteries (SIBs) gradually serve as a promising alternative to lithium-ion batteries (LIBs). Despite their higher safety profile compared to LIBs, thermal runaway (TR) remains a critical safety concern in sodium-ion battery systems. In this study, TR in SIBs [Na4Fe3(PO4)2 (P2O7), NFPP] is induced through electrical abuse experiments conducted at various charging rates, and electrical/thermal/gas/strain characteristics of SIBs during TR evolution are thoroughly investigated. Experimental results reveal that the evolution trend of key parameters during TR in SIBs closely resembled that of lithium batteries. By correlating internal electrochemical reactions with external electrical/thermal/gas/strain characteristics, TR in SIBs is divided into three stages. Compared to traditional voltage and temperature signals, strain and gas venting signals can provide earlier warning for SIBs TR. From the results, warning capabilities of multiparameters under different charging rates are analyzed, aimed at providing a more comprehensive reference for the TR warning of SIBs.