Well-dispersion of fillers in polymers is crucial for the preparation of mixed matrix membranes(MMMs). In this paper, COF-LZU1 particles were in-situ prepared in poly(ether-block-amide) membranes for the first time, and the as-obtained MMMs exhibited higher n-butanol/water sorption selectivity and pervaporation selectivity in comparison with that of MMMs prepared by conventional blending methods. The effects of reactants concentrations, growth temperature and solvents on property and pervaporation performance of MMMs were investigated. For the benzene-1,3,5-tricarbaldehyde (TFB) concentration of 2.0 mmol L-1, growth temperature of 70 degrees C, TFB to p-phenylenediamine molar ratio of 1:1.5, and solvent of n-butanol, the MMMs showed maximum separation factor (22.2) (increased by 139% in comparison with that of pristine membranes) and peameation flux of 611 g m(-2) h(-1), demonstrating great prospect for the recovery of n-butanol.