The invention discloses a water culture system and method suitable for close-planting-type plants. The water culture system comprises micro-nano bubble oxygen enrichment disinfection equipment, a nutrient solution pool and water culture grooves; the micro-nano bubble oxygen enrichment disinfection equipment and the nutrient solution pool are connected through a water inlet and return pipeline, andthe nutrient solution pool and the water culture grooves are connected through a water inlet and return pipeline. The water culture grooves are internally provided with planting plate supporting frames and planting plates, the planting plates are arranged on the planting plate supporting frames, and a plurality of rectangular planting holes are distributed in each planting plate at intervals andfilled with planting cotton. The water culture system and method have the advantages that seedling raising and planting are directly conducted in the water culture grooves, and secondary operation ofseedling raising and transplanting in different places is omitted; a micro-nano bubble aeration technology is adopted for oxygen enrichment, a nutrient solution has sufficient dissolved oxygen, the root systems of plants are developed, the water and fertilizer utilization rate is high, and the plants grow quickly.