On the threshold of elections designed to be held in February 2019, the first after the military junta seized power in 2014, it is important to define the role of parties in the political process of Thailand, which as other developing countries of Asia, faces challenges in democratic state/ building. The contemporary political history of kingdom represents the confrontation of two tendencies  – authoritarianism and democracy what has a reverse impact on political parties, their character, structure and ability to represent interests of the society as a whole. The author analyses the process of party evolution in the historical retrospective in the context of transformation of political system – from bureaucratic to semidemocratic subjected to economic modernization and changes in socio structure of society where traditional form of organization patron-client is persisted. The author defines three stages of evolution of party system in Thailand The first is characterized by the full control of civil-military bureaucracy over parties. The second stage is closely related to the formation of provincial political clientele groups. The third stage marks the evolvement of party of “power” with the implication for strengthening the parliamentary democracy in the beginning of XXI century. And as the result of it – to the destabilization of political system, based on the relative balance of power between two main political forces – bureaucracy and army interested in reservation of authoritarian government, and bourgeoisie supporting the liberalization of political institutes. With the emergence of party of “power” supported by the majority of population advocating parliamentary democracy political spectrum has changed. The arising conflict of interests subjected to collision of positions regarding the model of political governance was overcome by military coup. Analyzing the political spectrum on the threshold of elections the author comes to conclusion that the restoration of compromised model of political governance sample of 80-90 years of XX century is the most likely option of political development of Thailand in the near future. Though it differs in one aspect – the social structure has changed, there is the rise of that groups population that intend to participate in the political process, what will force the power  to be more transparent and social oriented. These challenges face the political parties as well.