This study collected 553samples of job seeker's interview. The method of this article is content analysis and critical incident technique (CIT). The final conclusion refers to 14 constraint factors of job seekers. Some factors such as "interest", "value", "health", "age", "motive", "family", "human skills", "economic pressure"… etc, which were presented from literatures. The study found that there are another 6 constraint factors: "self-handicapping", "dissonance of study and apply", "deficient in workplace information", "dilemma of target decision", "deficient in job-seeking skills", "deficient in confidence". Related employment service agents could have more completely views of making policies. In sexual category, one of the constraint factors of job seekers, the researcher pointed that almost male's constraint factors are lower than female's constraint factors, expect age constraint factor. There are some difference factors of "deficient in job-seeking skills", "family factor" and "self-handicapping" from 42% to 45% range. At the stage of career, the researcher found that "conversion period" is higher than "intermediate period", at the factors of "age constraint", "health constraint", "self-handicapping", "dissonance of career's value", "shoulder economic pressure". However "intermediate period" is higher than "conversion period", at the factors of "deficient in workplace information", "dilemma of target decision" and "exploring interest uncertainly".