The article considers the experience of the operation of the commercial police of the Russian Empire during the reign of Emperor Nicholas I. On the basis of departmental documents of the Ministry of Internal Affairs of the Russian Empire of 1840s, the author analyzed the problem of functioning of a special unit of the Russian police in St. Petersburg - the Commercial Police, which has not yet been the subject of independent scientific research. The study of the commercial police, as well as the process of ensuring economic security by this specialized police body, allows to overcome a variety of attempts of tactical criticism of the Nicholas era itself, studied in the domestic historiography tendency through the lensof the idea of the growth of crisis phenomena feudally – erfdom statehood of Russia. As a result of the study of the trade police, the author concluded that among the state reforms of the Nicholas era in Russia, which were assessed negatively, the organization of the Trade Police became a successful reform 1840-s. The Trade Police Organization allowed for the first time to abandon the foundations of the personnel policy, which was of a «pro-noble» character nature and to formulate the idea of an all-based principle of organizing the Russian police, which began to be implemented only in the 1860s and 1870s. Of particular importance in the article is the consideration of the experience of the Trade Police through the development of the pre-reform city and urban economy, which contributed to the formation of the functions of the Trade Police.