Modality alignment serves as the cornerstone for large multi-modal models (LMMs). However, the impact of different attributes (e.g., data type, quality, and scale) of training data on facilitating effective alignment is still under-explored. In this paper, we delve into the influence of training data on LMMs, uncovering three pivotal findings: 1) Highly detailed captions enable more nuanced vision-language alignment, significantly boosting the performance of LMMs in diverse benchmarks, surpassing outcomes from brief captions or VQA data; 2) Cutting-edge LMMs can be close to the captioning capability of costly human annotators, and open-source LMMs could reach similar quality after lightweight fine-tuning; 3) The performance of LMMs scales with the number of detailed captions, exhibiting remarkable improvements across a range from thousands to millions of captions. Drawing from these findings, we introduce the ShareGPT4V series for advanced modality alignment. It includes ShareGPT4V, consisting of 100K high-quality captions curated from GPT4-Vision; ShareGPT4V-PT, containing 1.2M captions produced by our Share-Captioner that can be close to the captioning capabilities of GPT4-Vision; and ShareGPT4V-7B, a simple yet superior LMM excelling in most multi-modal benchmarks, which realized better alignment based on our large-scale high-quality captions.