The present invention provides a fibrous IM-5 molecular sieve and the preparation process thereof. According to the process according to the present invention, by adding an appropriate amount of a quaternary ammonium salt with a long carbon chain to the preparation system so as to occur a synergistic action with the organic templet agent, an IM-5 molecular sieve which would be otherwise a rodlike form is converted into the fibrous form. The IM-5 molecular sieve according to the present invention has an aspect ratio greater than that of the rodlike IM-5 molecular sieve obtained according to the prior art, such that the proportion of the exposed periphery crystal face is higher, which benefit to increasing the selectivity of the catalytic reaction for the corresponding crystal face.