The invention discloses an adjustable coaxial laser nozzle for sending powder, comprising a laser head, a protection lens, a water-cooling sleeve for the protection lens and a column laser cavity arranged on the upper part, a coaxial conical laser cavity which is formed by the inner layer of a laser sleeve and arranged in the middle part, wherein a powder cavity, a secondary external protective cavity and an external water-cooling cavity are arranged on the lower part of the external part of the laser sleeve; the powder cavity is formed between the laser sleeve and a power cavity sleeve screwed together; the secondary external protective cavity is formed between the powder cavity and a protective air casing screwed together; the powder cavity and the protective sir casing are screwed together and adjustable between 1mm to 3mm; 4 to 6 power transmitting pipes and 4 to 6 air tubes are respectively positioned around the top parts of the cones of the powder cavity and the protective air cavity. The adjustable coaxial laser nozzle for sending powder has the advantages that the focus length of the focus lamp fit for the coaxial powder-sending nozzle is between 100mm to 300mm, which ensures convenient assembly and disassembly, even velocity, flexible adjustment of the powder converge diameter, convenient changeable lower coaxial conical parts (the powder cavity, the air casing and the water cavity).