Depends on what interface you want to use. As long as you do not want to executer code from the flash memory you could use I2C or SPI interfaces. There is an external memory interface component, but I didn't check (yet) if that works with flash.
Just for curiosity: What do you need 2 MB for?
2MB flash for log data from device.I thought CY8C5267AXI-LP051 doesn't have SPI ,what about UDBs and I/O ports can I use that for external flash
pls refer this data sheet http://www.cypress.com/file/45916/download at 5.6
There are plenty of interfaces on your chipbased on UDBs. They can be configured to act as UART, SPI, I2C and some more. I would suggest you to download and install Creator 4.2 and start a project with your selected device. The Component catalog will show what components are availlable and the resources tab will show (after a build) the usage.
PSoC Creator offers the External Memory Interface Component (EMIF) which can be used to interface with your 2Mb Flash.
These resources will be helpful:
2) Page#21: http://www.cypress.com/file/45916/download