Abstract: To investigate the effect of K⁺ on the properties and mechanism of the composite gel system consisting of tamarind gum and κ-carrageenan, four methods including rheology, texture analysis, microstructure, and infrared spectroscopy were used to investigate the properties and structure of the composite gel with different K⁺ additions. The rheological results showed that the addition of K⁺ increased the modulus of the gel system and decreased the compliance and total deformation. When the addition of K⁺ increased to 15 mmol/L, the apparent viscosity reached its highest value of 2690 Pa·s. The results of texture analysis revealed that the strength and hardness of the gel system increased with the addition of K⁺, but its elasticity and cohesiveness decreased relatively. Infrared spectroscopy and microstructure demonstrated that K⁺ could promote the interaction between tamarind gum and κ-carrageenan, the gel pores tend to be dense and uniform, and the inter-pore walls were most regular and strong at the K⁺ addition of 15 mmol/L. The results showed that the addition of K⁺ could make the gel system exhibit better viscoelasticity and anti-deformation, and make the network structure more compact, which would provide a theoretical reference for the application of tamarind gum and κ-carrageenan in compounding.