The key of finding high quality reservoirs in hydrocarbon exploration is predicting secondary porosity zones, especially in deeply tight siliciclastic reservoirs. Mechanism of forming secondary porosity is numerous in siliciclastic reservoirs and the mechanism of meteoric water leaching is ignored because minerals formed by dissolution of meteoric water in eodiagenesis were transformed by late diagenesis. Meteoric water leaching of siliciclastic rocks in eodiagenesis and epidiagenesis at home and abroad, and water—rock interaction of experimental imitation are studied by typical examples. Results show that there are close relationship between secondary porosity and meteoric water in siliciclastic reservoirs. Reaction products can be taken away immediately, because the reaction of meteoric water and unstable minerals happens in open and semi closed diagenetic systems, then water—rock interaction continues and secondary porosity increases. Secondary porosity zones caused by meteoric water leaching can be predicted by reservoirs petrophysics and sequence stratigraphy.