Quantitative trading using mathematical models and automated execution to generate trading decisions has been widely applied acorss financial markets. Recently, reinforcement learning (RL) has emerged as a promising approach for developing profitable trading strategies, especially in highly volatile markets like cryptocurrency. However, existing RL methods for cryptocurrency trading face two critical drawbacks: 1) Prior RL algorithms segment markets using handcrafted indicators (e.g., trend or volatility) to train specialized sub-policies. However, these coarse labels oversimplify market dynamics into rigid categories, biasing policies toward obvious patterns like trend-following and neglecting nuanced but lucrative opportunities. 2) Current RL methods fail to systematically use demonstration data. While some approaches ignore demonstrations altogether, others rely on “optimal” yet overly granular trajectories or human-crafted strategies, both of which can overwhelm learning and introduce significant bias, resulting in high variance and significant profit losses. To address these problems, we propose ArchetypeTrader, a novel reinforcement learning framework that automatically selects and refines data-driven trading archetypes distilled from demonstrations. The framework operates in three phases: 1) We use dynamic programming (DP) to generate representative expert trajectories and train a vector-quantized encoder-decoder architecture to distill these demonstrations into discrete, reusable strategic archetypes through self-supervised learning, capturing nuanced market-behavior patterns without human heuristics. 2) We then train an RL agent to select contextually appropriate archetypes from the learned codebook and reconstruct action sequences for the upcoming horizons, effectively performing demonstration-guided strategy reuse. 3) We finally train a policy adapter that leverages hindsight-informed rewards to dynamically refine the archetype actions based on real-time market observations and performance, enabling more fine-grained decision-making and yielding profitable and robust trading strategies. Extensive experiments on four popular cryptocurrency trading pairs demonstrate that ArchetypeTrader significantly outperforms state-of-the-art approaches in both profit generation and risk management.