My website indexed well in Google.But there was no description in search results when I used site command to search some pages of this website.Instead,there was only the title of the page and its address.Now the key words rank of these pages is not good.May I ask what's the reason for this situation？And how to improve it?
there must be a problem in metadata you are passing... try to solve the meta problem in the webpages of your site... and yes there must be the meta format which is seo friendly and you should try to tweak the homepage a little bit so that your website's description should be included in the google search engine rankings.
If your website is new then Google will take some time to index content.... If Google is not displaying your description then there is something wrong with your description tags. Make sure your description of your website should be in Meta description tag. The HTML suggestions page in Webmaster Tools lists pages where Google has detected missing or problematic meta descriptions. (To see this page, click Diagnostics in the left-hand menu of the site Dashboard. Then clickHTML suggestions.)
have you checked your setting's in your admin, some platforms like wordpress have a setting to deny search engines indexing and if your using joomla there is an area for the site description aswell you should check. if you have a site that isnt a CMS or Blog check your meta tags are ok.
will you please provide url of your site, so we can analyse it. May be your are using nodp in meta part.
Yes,i used nodp in meta part like "<meta name="robots" content="noodp,noydir" />" but all my website page used this meta also,the most pages are normal. My website useing Zencart.