While engaging in corporate social responsibility (CSR) has gradually become mainstream in the business context, the investigation of CSR communication and its effectiveness remains limited. This study examines how environmental CSR communication affects consumer perception and behavior through an experiment design. We distinguish three CSR communication factors—message content (climate responsibility vs. sustainable use of natural resources), message style (greenhushing vs. uniform vs. greenwashing) and praise tactics (consumer praise vs. company praise)—and assess their impacts on consumer trust, purchase intention and consumer advocacy, respectively. We also investigate the moderating role of attributed intrinsic and extrinsic corporate motives on engaging in environmental CSR. An online experiment (N = 304) revealed that a uniform message style outperforms the other two styles, whereas greenwashing is found to be least effective. In addition, attributed intrinsic corporate motives moderate the impacts of environmental CSR communication on consumer trust, purchase intention and consumer advocacy, respectively. No moderation effect was found for attributed extrinsic corporate motives. The findings provide important implications for effective environmental CSR communication with respect to specific message styles and attributed corporate motives.