The difference between direct sales and self-operation on AliExpress is mainly reflected in the following aspects:

1. Sales model: Direct sales refers to the direct sales of goods to buyers by AliExpress, while self-operation refers to AliExpress operating its own goods, purchasing, logistics, sales, etc.

2. Source of goods: Direct sales may come from multiple suppliers, while self-operation goods come from AliExpress itself.

3. Quality control: AliExpress is responsible for the quality control of direct sales, while AliExpress's own procurement and quality control team is responsible for the quality control of self-operated goods.

4. Brand image: AliExpress is responsible for the brand image of direct sales, while AliExpress's own brand team is responsible for the brand image of self-operated goods.

5. After-sales service: AliExpress is responsible for the after-sales service of direct sales, while AliExpress's own customer service team is responsible for the after-sales service of self-operated goods.

In general, the difference between direct sales and self-operation lies in sales model, product source, quality control, brand image and after-sales service.