With the steady growth of our nation's economy, the purchase power of our domestic citizens has continuously enhanced. In recent years, online overseas shopping has rapidly warmed up, increasing number of Chinese people have started to purchase overseas products via internet. According to China's current legislation, the imported goods are divided into goods and items based on "profitability standard", and regulated by different rules of clearance supervision and import duties. Goods can't pass through custom and pay duties in the form of items, and the import duties burden of goods is generally much heavier than that of items. Goods of entrusted overseas shopping pass through custom and pay duties in the form of items, but goods of profitable purchasing are goods, not items. Therefore, the profitable-purchasing behavior is smuggling. Although goods of unprofitable purchasing are items, unprofitable-purchasing behavior may also constitute smuggling. The author concludes that causes of smuggling crime are: huge market demand for overseas goods, lack of customs supervision, law blank of petty foreign trade, and public's misconception of entrusted overseas purchasing are the major factors. The author proposes the corresponding preventive measures against the crime, such as to establish an one-stop service system in online Shopping Mall, to modify the Passengers' Baggage Declaration Form, to establish a relatively simplified clearance system of small cargo, to establish a relatively reasonable import duties of petty trade.