I would suggest that you read through this link:
What are the differences between the PYNQ-Z1 and PYNQ-Z2 boards?
The PYNQ-Z1 and PYNQ-Z2 boards share a number of similarities. They both have a Zynq 7020, 512MB DDR, 10/100/1000 Ethernet, USB, SD card boot.
The main differences are the expansion headers, and the audio systems.
The PYNQ-Z1 has 2 Pmods, an Arduino header, and ChipKit header. The PYNQ-Z2 also has 2 Pmods, and an Arduino header, but replaces the ChipKit header with a 40-pin Raspberry Pi header. (Note the Raspberry Pi header has 26 data pins connected to the PL. 8 of these pins are shared with Pmod A).
The PYNQ-Z1 has an integrated MIC with PWM input, and mono PDM audio out. The PYNQ-Z2 has a full ADI audio codec with Headphones out, Mic, and line in.
The boards also have slightly different dimensions.