This paper presents the Chart-R1 model, which applies an R1-style method based on reinforcement learning fine-tuning to complex inference in the chart domain. Unlike existing R1-style methods that focus on mathematical reasoning and code intelligence, Chart-R1 enhances inference capabilities for more general multimodal data, particularly chart data. To achieve this, we propose a novel programmatic data synthesis technique that generates high-quality step-by-step chart inference data containing single and multiple sub-charts. We also develop a two-step learning strategy: Chart-COT, which utilizes a Chain-of-Thought (COT) map, and Chart-RFT, which utilizes numerical sensitivity fine-tuning. Chart-COT decomposes complex inference tasks into fine-grained sub-tasks, while Chart-RFT emphasizes numerical sensitivity in the chart domain by using relatively gentle rewards for numerical responses. Experimental results show that Chart-R1 outperforms existing chart domain methods and is comparable to large-scale models such as GPT-4o and Claude-3.5.