In the UK mobile phone dialling, also need to add +44 ?

If you know the number, you don't need to add 44, just dial directly. If you store the number in advance in China, it is better to add 44, whether it is 0044 or +44. If you don't add it, the domestic mobile phone will automatically add +86 for you. If you use a UK phone, dial +442033181066.

"You don't need to add anything."

No, just replace +44 with 0.