The customized bus (CB) is an innovative and environmental supplementary mode of public transport, providing demand-responsive and user-oriented service to specific passenger groups with similar travel demands, especially commuters, based on online reservations. However, sufficient travel demand is essential for the successful operation of CB. The purpose of this study is to analyze the factors influencing the attraction of CB to commuters, which is tied to the ordered mode shift decisions, do no transfer to CB, remain undecided, and transfer to CB. A combination of revealed preference (RP) survey and stated preference (SP) survey is conducted among commuters in Beijing through online and offline questionnaire, collecting 1304 valid commuting demands. The ordered logit (OL) model and two-level mixed-effect ordered logit (MEOL) model are used to estimate the variable effects and the difference in five commute modes, including car, taxi, bus, rail, bus + rail, is considered. Common variables significantly influencing the transfer decision in all groups are specified in models, including familiarity to CB, seat availability, and gender. Meanwhile, travel cost, travel time, and transfer time of the current travel mode have positive effects on the attraction of CB. In addition, car ownership and accessibility to bus stations also influence the attraction of CB to certain group commuters. This paper can provide references to CB operators for formulating differentiation strategies and attracting more passengers in Beijing.