Weathered red sandstone soil has weak water stability, unsatisfactory mechanical and poor engineering properties, which limits its utilization. When the proposing expressway through the soil, a large number of abandoned would be generated, which would burden construction costs and bring about many adverse effects to the local environment. To turn waste into treasure, the improving experiment with EN-1 soil stabilizer was conducted. Through the unconfined compressive strength test, the optimal mixing ratio of EN-1 soil stabilizer was identified as 0.014%. Series of tests on the road performance indexes were carried out under the condition of the optimal ratio of EN-1. The test results showed that 28d strength of the improved soil achieved 2.98MPa, 7d water stability coefficient achieved 0.75, the improved soil possessed good engineering properties, which can meet the requirements of expressway pavement materials.