Phytoremediation mediated by microorganisms in the rhizosphere is a promising technology for the effective management of petroleum hydrocarbons-contaminated soil. However, it is essential to explore the dynamics of the micro-environment in the rhizosphere during phytoremediation process. A pot xperiment was conducted to investigate the ecological response of rhizospheric environmental of landscaping plant (Helianthus annus) to the petroleum hydrocarbon compounds (PHCs) contamination. The results showed that the species had a high ability to remove PHCs, and the removal of n-alkanes largely depended on symbiotic microorganisms in the root zone. The remediation efficiency of Helianthus could be regulated by rhizosphere microbes through the enhancement of nutrients and energy cycling, remodeling of the beneficial bacterial abundance, and improvement of enzyme activities. In addition, the ecological response of rhizosphere soil was closely related to the root exudation effect of plant and PHCs exposure. The present study provides information about the succession pattern and response of the microbial community of rhizosphere soil in the PHCs phytoremediation of Helianthus annus, and demonstrated the feasibility of Helianthus annus in the effective management of PHCs in contaminated soil. Display omitted