Abstract: ［Purpose/Significance］Based upon the Heuristic-Systematic Model (HSM), this paper chose space-time limitation and task complexity as heuristic and systematic clues respectively to build a theoretical model and explore the impact factors of these two clues on search results. Then it compared the different effects of space-time limitation and task complexity on search results when using different search devices.［Design/Methodology］The paper designed a 2 (space-time limitation: high vs.low) X2 (task complexity: high vs.low) X2 (search device: only mobile phone vs.both mobile phone and PC) multi-factor experiment and built eight different search situations. A total of 200 college students who have searched both by mobile and PC participated in the online experiment to investigate the influences of heuristic and systematic cues on search behaviors and results.
［Findings/Conclusion］According to the length of search time, search behaviors were divided into heuristic and systematic behaviors. For the heuristic search behaviors, the match of search results was only affected by space-time limitation; and for the systematic search behaviors, both spacetime limitation and task complexity had significant effects on the match of search results. In addition, the effects of space-time limitation and task complexity differ on the match of search results when using different search devices (e.g.the use of mobile phone and the use of both mobile phone and PC).［Originality/Value］This paper not only reveals heuristic and systematic models of search behaviors, but also discovers their influencing factors, which could help to improve search products and services.

Key words: Space-time limitation, Task complexity, Search behavior；Cross-device, Heuristic-Systematic Model