As you are probably aware China does not play nice with Google services and for the last two years Gmail has virtually been unusable in mainland China. Below our top 5 alternatives if you need to use email for your business while in China.
1) Outlook / Office365: probably the strongest Gmail/Google Apps for Work alternative, and a worldclass mail service with excellent delivery. Two server options to consider: mainland China (offered by Microsoft in partnership with 21Vianet) or Hong Kong. While mainland China servers are theoretically fasters to access from the country, the privacy of data hold by Chinese operators is always a concern. As such, international companies are recommended in general to select the Hong Kong-hosted service. Both are offered by SinoHosting.
2) Corporate Email solutions offered by Chinese internet companies: many large Chinese internet conglomerates offer business email hosting which is generally reliable. English support can be a hit or miss. Some examples include:
3) Using a VPN: this would allow you to use Gmail as usual but there were cases where the Chinese firewall blocks or interferes with these VPN. So this is a temporary solution at best.
4) Using Gmail/Google Apps but with a mail client: Some users have reported having no issues accessing their Gmail accounts through a mail client such as Microsoft Outlook or Thunderbird.
5) Using the email function of a standard web hosting account in Hong Kong: many Hong Kong web hosts such as KowloonHosting offer business email accounts that can be used only for emails if the necessary DNS records are configured correctly. If some users are based outside China, or you plan to travel frequently outside China, this would be a recommended solution as access to email servers based in mainland China from overseas can also be problematic due to the same Great Firewall issues.