"发展潜力大的市场" can be translated into English as "a market with significant growth potential" or "a market with high development potential".
Both expressions convey the idea that the market has a strong capacity for future expansion and success. You can choose the one that best fits the context or your personal preference.
For example:
"Our company is focusing on exploring a market with significant growth potential."
"Investing in a market with high development potential can yield substantial returns."