We collected data on environmental protection and economic growth targets in Chinese prefectures during the 11th, 12th, and 13th Five-Year Plan periods and applied spatial autoregressive models to investigate the impact of mandatory environmental targets on local governments' economic growth targets. We found that comprehensive mandatory environmental targets allocated by provincial governments lowered prefectural governments' aspirations for economic growth. But this negative relationship was weakened by relative pollutant emissions efficiency. Additionally, economic growth targets set by prefectural governments were positively affected by their past goals, past performance discrepancies, the goal levels set by their geographically and strategically proximate peers, and the goal levels set by provincial governments. Mayors nearing retirement exhibited a significantly negative impact on economic growth targets, while the education level of Communist Party secretaries demonstrated a significantly positive influence. Further analysis showed that these environmental targets not only negatively affected local governments' aspirations for economic growth but also suppressed actual economic development to a certain extent. Our findings offer empirical insights into understanding local governments' strategic decision-making in balancing economic development and environmental protection.