Electoral studies have been long debating on the legislative professionalization on the election results and reach no consensus on how the party functions under the framework of professionalism in shaping the election in democratic regimes. Hong Kong, a constrained democratic system embedded within an authoritarian regime, has also gone through its own nuance of party politics. Yet, little research has comprehensively scrutinized the evolution of the legislative professionalization in Hong Kong. This study employs the electoral data of all candidates (N =967) from the Hong Kong Legislative Council (LegCo) since the first direct election in 1991 to the most recent one in 2016. The data reveals that the dynamic mechanisms of legislative professionalism from three levels. First, political party matters through the network resources they owned. Second, the ideological impacts of a candidate’s party affiliation are stronger than the resources a party can offer and the candidates’ personal attributes. And such ideological bonus is beneficial to the pro-Beijing camp and the pro-democratic candidates over time due to the institutional guarantee. Third, candidates who owned the esteemed occupational orientation will be more likely to win, which indicates the industrialization and professionalism have a strong influence in Hong Kong politics. The empirical findings offer evidence to further discuss Hong Kong politics and the impacts of the upcoming 2020 election.