Polysaccharide hydrogels possess weak mechanical properties because of their high water content. Herein, a simple, facile, and green method for preparing a polysaccharide hydrogel spanning a 100-fold range in ultimate stress (from 10 kPa to 1 MPa) with high water content (60-90%) is developed. Without modification or complicated preparation methods, hydrogels based on gellan gum can reach the ultimate stress at 1 MPa by utilizing the permeation and further cross-linking of the divalent solution. Moreover, the hydrogel pore size, biodegradation, and transmittance vary according to the concentration of the polymer and the divalent cations. Given the highly tunable mechanics, pore size, degradation, and transmittance properties of gellan gum hydrogel, it may be applicable for a wide range of biomaterial approaches and large-scale manufacturing.