Currently, Taobao and Pinduoduo are two independent e-commerce platforms, and there is no direct data transmission channel between them. Therefore, if you want to upload videos on Taobao to Pinduoduo, you need to manually download the videos from Taobao to your local computer, and then upload them on Pinduoduo.

The specific steps are as follows:

1. Open Taobao and find the video you want to download.

2. Use third-party tools or browser plug-ins to download the video to your computer or mobile phone. Commonly used tools include Thunder, IDM, etc.

3. Open the Pinduoduo merchant backend and log in to your merchant account.

4. Enter the product management page of the Pinduoduo merchant backend.

5. Click "Add Product", select the product category to which the video to be uploaded belongs, and fill in relevant information, such as product title, price, inventory, etc.

6. On the product editing page, find the location where the video is uploaded, which is usually in the product details section.

7. Click the Upload button, select the previously downloaded video file, and upload it to the Pinduoduo merchant backend.

8. After confirming that the product information is correct, click Save and Submit for Review.

It should be noted that Taobao and Pinduoduo are two different e-commerce platforms, and there will be certain differences in the product listing process, pricing strategy, etc., so before uploading to Pinduoduo, it is recommended to first understand Pinduoduo's rules and requirements to ensure the accuracy of the product information and comply with Pinduoduo's regulations.