How to root Sony Xperia Z 
This procedure is tested on C6603 model but it works on C6602 model also. Prior to rooting, your system should be working on 10.1.A.1.350 firmware version and your boot-loader must be unblocked. Now let’s move to main part. Follow this procedure to root your Xperia Z: 
1. Follow these pre-requisites. It will help your device to stay away from all security threats. 

2. Download ADB to your compute (from android.com). 

3. Download modified CF-Auto-Root kernel and Stock insecure kernel for FW (10.1.A.1.350) to your computer. Don’t rename any of the files. 

4. Download ROM manger app from play store. 

5. Now using the ROM Manger app, boot your device to bootloader mode (you may find manual instructions on device manual book too). 

6. Now take USB cord and connect Xperia Z with the computer n which above two files are downloaded. 

7. Open Command Prompt and enter these code: 

• fastboot flash boot Z_DooMLoRD_CF-Auto-Root-ported_FW-350.img
• fastboot reboot
• fastboot flash boot Z_DooMLoRD_insecure_FW-350.img
• fastboot reboot

8. That’s it! You have rooted your Sony Xperia Z and now you can play with all rooting required apps/guides etc. 

You can anytime check your rooting status by help of Root Checker App from Google Play Store. In case you need any kinds of help from my side then please let me know through your comments.