Composition and component content of crude phenols from low temperature coal tar were analyzed by GC-MS, the main properties and multi-element interaction parameters of non-library components in crude phenols were estimated and evaluated by Aspen Properties software. Vacuum distillation processes of four columns combination were simulated and optimized by Aspen Plus software. The reliability of above optimization conditions was also verified. The results showed that 23 phenolic compounds were detected, which occupied 97.806% mass content in crude phenols. Compared with 89.436% of lower phenols, the content of higher phenols was very low, but they had more varieties. Estimation outcomes of non-library components in crude phenols would greatly satisfy the accuracy of numerical simulation. The optimal theoretical plate number and feeding location were 90, 80, 70, 60 and 55, 30, 39, 32, reflux ratio 15.52, 15.95, 15.87, 0.98 in phenol tower, o-cresol tower, p-cresol/m-cresol tower, dimethylphenol tower, respectively. The average mass purity and yield of top column products containing phenol, o-cresol, p-cresol/m-cresol and dimethylphenol could completely meet the demands of specified requirement after experimental verification.