The continuous and highly intergrown CoAPSO-5 membranes were synthesized on the α-Al2O3 substrates by in situ crystallization, which was studied focused on effect of Co content. According to the characterization of scanning electron microscopy (SEM), X-ray diffraction (XRD) and inductive coupled 〖JP2〗plasma emission spectrometer (ICP), the zeolite membranes were composed of well-intergrown CoAPSO-5 crystals, which lost their own morphology and tightly covered on the α-Al2O3 substrate in random orientation. Meanwhile, the Co content of the CoAPSO-5 crystal and its influence on the morphology, the thickness and the completeness of CoAPSO-5 membranes were studied. The gas permeation measurement revealed the resulting membranes were of high-quality with few non-zealitic pores.