Chemical composition of particulate matter (PM) from traffic emissions vary by region and time. Therefore, it is necessary to obtain local mobile source profiles of PM to support regional researches for vehicle emission control policy, source apportionment modeling, etc. In this study, PM2.5 and PM10 samples were collected from a highway tunnel in Xi’an, northwestern China. Detailed chemical composition, including OC, EC, water-soluble ions, and elements, were analyzed to (1) provide a local PM profile with mixed vehicle fleet, (2) identify the origins of different elements in the tunnel environment, and (3) determine the associated factors influencing PM profiles. The PM2.5 profiles in the tunnel included OC (34.10%), EC (11.96%), water-soluble ions (18.22%), and elements (27.73%), while the PM10 profiles included OC (28.48%), EC (8.59%), water-soluble ions (14.17%), and elements (33.36%). The origins of the elements in the tunnel were classified into three categories by the receptor modeling approach, which included resuspended road dust and brake wear, vehicle exhaust and tire wear, and tailpipe emissions from diesel vehicles (DV).The mass fractions of OC, EC, and elements originating from resuspended road dust and brake wear were mainly affected by vehicle driving conditions (i.e., uphill/downhill and speed), whereas the mass content of bromine (Br) was influenced by the proportion of DV in the fleet.