Sherry700700 wrote:
I want to buy Apple watch series 3 gps + cellular can it connect with iPhone 4s
No, according to: Set up your Apple Watch - Apple Support
"To use Apple Watch Series 3 (GPS + Cellular), you need an iPhone 6 or later with the latest version of iOS. (To use Apple Watch Series 3 (GPS) or earlier models of Apple Watch, you need an iPhone 5s or later with the latest version of iOS."