This study examined the effects of presentation unit (word-by-word or single line) and presentation duration [171, 213, 240, and 308 msec. per character (msec./C)] on the comprehension of Chinese rapid serial visual presentation (RSVP) displays read from the small screen of a mobile phone in three different contexts (seated, walking on a treadmill, and walking through an outdoor course). 30 native Chinese readers ages 19 to 26 were recruited as participants. Scores on reading comprehension showed that presentation unit and presentation duration significantly affected reading comprehension, and interactions between factors were also significant. When the presentation unit was word-by-word, no significant difference in reading comprehension was observed under different presentation durations. However, when the presentation unit was a single line, reading comprehension deteriorated with the shortest presentation duration of 171 msec./C. With regard to context, participants had a higher mean reading comprehension score in the seated context than in walking contexts, but the difference was not significant.