Transit accessibility should take transit timetable into account and be time-dependent. The reason is that the maximum passenger carrying capacity of a transit station is determined by the scheduled timetable. In addition, passengers always choose departure time according to their own need, which varies with time. Based on the traditional two-step floating catchment area (2SFCA) and gravity method, this paper proposes two new methods to evaluate transit accessibility. The proposed methods are implemented to evaluate the bus accessibility of Xiamen City, China. According to the local bus timetable, a typical workday is divided into three periods. Within each time period, bus travel supply-to-demand ratios by station are calculated and then aggregated into the traffic analysis zone (TAZ). The empirical findings show that fluctuations in travel demand and the passenger carrying capacity of bus stations in different time periods make the bus accessibility significantly differ throughout the city. They also show that bus accessibility based on the extended 2SFCA model are equivalent to that based on the extended gravity model, when the total demand is relatively lower than the total passenger carrying capacity of a bus station.