The invention discloses an inner cone ring of a heavy truck gear box synchronizer and a manufacturing process thereof. The substrate is a power metallurgy material which is prepared from the following raw material components in percentage by weight: 0.5-5% of copper powder, 0.1-1.5 % of graphite powder, 0.1-1.5 % of free cutting agent, 0.2-2% of lubricating agent, 0.01-1.5% of bonding agent, and the balance of 88.5-99.09% of iron powder. The manufacturing process of the inner cone ring has the following steps: materials mixing, forming, sintering, auxiliary machinery processing, vapor treatment, and bonding. According to the invention, powder metallurgy process is adopted, and wicking treatment is carried out in the sintering process, thus the intensity at the position born greater stressof the outer cone ring blank is improved prominently, and using performances of products in the synchronizer are increased; and the process is simple and reliable, the production efficiency is high, the material utilization ratio is high, and inner cone ring products which are manufactured in bulk have the advantages of stable quality, high intensity, high manufacturing accuracy, low manufacturing cost and the like.