The need for clean water continues to increase along with population and industrial growth, which causes a water crisis. Quantitatively, peat water has the potential to be managed as a source of clean water using membrane filtration. This study aims to compare the composition of the cellulose acetate-zeolite composite membrane in reducing TDS levels in peat water using a cross-flow reactor. Cellulose acetate-zeolite composite membranes were prepared by phase inversion technique using 15 wt.% cellulose acetate (CA), with variations in zeolite concentration (5%; 10%; 15%; 20% and 25%), contact time (20, 40 and 60 minutes), the reactor pressure was 1.5 bar, and the TDS concentration in the feed water was 1,201 mg/L. Membrane characterization was done through morphological analysis using a Scanning Electron Microscope (SEM) and tensile test analysis. Membrane performance is determined through permselectivity and permeability testing. The results showed that the highest flux value was obtained on a 5% cellulose acetate-zeolite membrane at the 20th minute, namely 78.8 L/m2.hour. The best composition was obtained on a 25% cellulose acetate-zeolite membrane with a tensile strength value of 54.089 MPa and a rejection value of 92%. Morphological characterization showed that the pore size of the cellulose acetate-zeolite composite membrane decreased after use because TDS particles covered it.