The purpose of present study is to examine the relative efficacy of two active exercise programs for work-related chronic low back pain and to figure out how much they are affecting lumbar`s mechanical stability. Subjects are 43 employees with work-related chronic low back pain, and they were randomly divided into two groups with general physiotherapy groups, lumbar exercise groups for lumbar deep muscle reconditioning. Active exercise programs were done 3 times a week, for 6 months, and subjects are tested of Pain intensity(VAS), Oswestry Disabilty Index, Lumbar stability. All subjects were reassessed with same measurement with Pre-study, 2 weeks after study, 3 months, 6 months. After applying two active exercise programs, pain intensity recored among four time-points for each group decreased significantly (p<0.05) even though they didn`t show significant difference among two groups. Oswestry Disability Index showed significant difference among two groups on 6 months and Index of lumbar exercise groups decreased significantly compare to physiotherapy group(p<0.05). Lumbar region incline angle showed significant difference among two groups on 2 weeks, 3 months, 6 months, and lumbar group decreased significantly rather than physiotherapy groups (p<0.05).