The study of silicalite is a rather difficult yet quite important subject, and the petrochemical method is an important means for studing its genesis and rock-forming environment. Based on a preliminary test of nearly twenty common ration methods and graphic methods, this paper has examined their feasibility. The "Jingtieshan type" iron deposits are distributed in Middle and Upper Proterozoic Jingtieshan Group in the western part of North Qilian Mountain, where tens of iron deposits(ore spots) have been disvovered. Among them, the Jingtieshan iron deposit is large-sized, and the Liugouxia and the Baijian iron deposits and belongs to grrenschist facies epimetamorphic rocks, with its bottom being medium-thick stratiform quartzite. Within the Jingtieshan type iron deposits there exists ferrojasper rock associated in banded form with specularite, and hence the study of the formation environment and genesis of ferrojasper rock means the study of the formation environment and genesis of Jingtieshan type iron deposits. The authors colleted ferrojasper rock samples and surrounding quartzite samples from the Huashuaguo and the Liugouxia iron deposit, used petrochemical research method for silicalite and compared the silicalite with typical silicalite in the world. The conclusions reaches are as follow:(1) the quartzite in wall rocks of the Jingtieshan type iron deposits shows character of biogenic silicalite and results mainly from surface weathering, while the ferrojasper rock in iron orebodies exhibits igneous character and is derived from submarine exhalation; (2) geochemical characteristics of quartzite and ferrojasper rock in Huashugou and Liugouxia demonstrate that these two iron deposits were formed in similar geological environments and should both belong to Jingtieshan type iron deposits.