Microporous　polyacrylonitrile　membranes　were　prepared　via　the　combination　of　thermally　and　chemical　reaction-introduced　nonsolvent-induced　phase　separations　(TIPS　and　CRINIPS).　In　the　membrane　preparation,　glacial　acetic　acid　(GA)　and　aqueous　solution　of　2　wt.%　sodium　bicarbonate　were　used　as　additive　and　coagulation　media,　respectively,　and　chemical　reaction　between　GA　and　sodium　bicarbonate　resulted　in　uniform　microporous　membranes.　Pore　connectivity　and　asymmetry　were　significantly　improved　when　coagulation　bath　temperature　was　lowered　to　15　degrees　C.　The　fouling　mechanisms　of　the　prepared　membrane　were　analyzed　by　nonlinear　regression　method　and　cake　filtration　model　was　the　most　appropriate　for　the　membrane　prepared　via　combining　TIPS　and　CRINIPS.　The　pore　structure　was　made　connective　and　asymmetric　by　using　a　15　degrees　C　aqueous　solution　of　2　wt.%　sodium　bicarbonate　as　coagulation　media　in　membrane　precipitation　process,　and　the　average　pore　size　reduced　from　about　0.125　to　0.097　mu　m　while　decreasing　the　glass　plate　temperature　from　80　to　20　degrees　C.