Lithocaps generally show steep topography on the surface. They are formed by high temperature and high oxygen fugacity acid hydrothermal fluid leaching the surrounding rocks to form a series of advanced argillic and argillic mineral assemblages. These alteration minerals are a part of the epithermal alteration system and show the potential to search for porphyry mineralization underneath. “Secondary quartzite”, a term defined by predecessors to describe alteration systems, are widely developed in volcanic systems in the southeastern Zhejiang Province. In this paper, we investigate the Houkeng lithocap using large- scale alteration mapping, core logging, and using short- wave infrared (ASD), Electron probe microanalyzer (EPMA), scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS) and other analytical techniques. We found that the lithocap shows vertical and horizontal alteration zoning. Vertical alteration grading occurs from corundum- sericite at depth, through sericite- pyrophyllite, to alunite- kaolinite- quartz zoning at shallow levels. Horizontally, vuggy quartz- rutile developed in the core, grading to advanced argillic (alunite- pyrophyllite- kaolinite- diaspore- diaspore- Aluminum phosphate and sulphate minerals), and argillic (kaolinite- illite- montmorillonite) alteration. We reached the following conclusions: ①The short wavelength infrared (SWIR) spectrum absorption peak of the Houkeng alunite ranges from 1480 nm to 1491 nm. These alunite, originating from magmatic- hydrothermal alteration, are mainly composed of potassium alunite, with a small amount of sodium alunite; ②Pyrophyllite, whose short wavelength infrared (SWIR) spectrum absorption peak at 2167 nm, shows two origins: sericite retrograde alteration and kaolinite metamorphism; ③corundum is altered to sericite by hydrothermal alteration in the later stage, and phyllic alteration may develop below the corundum- sericite zone; ④diaspore is transformed into dickite by later hydrothermal fluid, which indicates multiple stages of fluid alteration. Comparing the lithocap with the other porphyry- epithermal deposits’ alteration zonation (like Horse- Ivaal,Vuda et al), we propose that the Houkeng lithocap is the upper part of the porphyry- epithermal alteration system and shows the potential for locating porphyry deposits beneath the base of the lithocap. At the same time, it is suggested that other lithocaps developed in volcanic rocks in southeastern Zhejiang also belong to this alteration system and hold great potential for prospecting for porphyry copper- gold deposits.