In order to explore the biological and ecological effects of garlic on overcoming the continuous cropping obstacles of tomato in the facility and to produce forcing garlic at the same time, the experiment was conducted by choosing four garlic cultivars and three interplanting dates. The growth, development and yield of different garlic cultivars by the different interplanting dates are emphatically analyzed in this paper. The results show that sprouting duration for S1 (sowing on August 25) is much longer than that for S2 (sowing on September 9) and S3 (sowing on September 24), but the sprouting date for S1 is much earlier than that for S2 and S3. Garlic plant growth for S1 shows more advantages to the two later sowing treatments in the index of maximum leaf length, leaf width, sheath height, sheath width, plant height, root number and leaf number. Plant growth of cv. G64 appears preponderant to the other three cultivars in maximum leaf length, leaf width, sheath width, plant height and root number. Early sowing promotes bulb development. Among four cultivars, cv. G64 ranks first and cv. G87 ranks the next in bulb characters of maximum width, minimum width, height and perimeter. Bulb weight of cv. G64 is very significantly heavier than that of the other three cultivars, the bulb yield of cv. G64 is the highest. Interplanting cv. G64 with tomato on the date of S1, garlic bulb harvest time is 30—35 days ahead to the garlic on open land, and the garlic price enhanced 60%. Therefore, cv. G64 and August 25 are recommended as suitable cultivar and interplanting date in the tomato/garlic interplant system in the facility.